This invention relates generally to catheters and more specifically to a catheter for draining urine from the human bladder.
A bladder catheter is a long tubular device which is inserted through the human urethra into the bladder to drain urine. In order to prevent the catheter from being inadvertently withdrawn from the bladder, one commonly used catheter utilizes an inflatable balloon which surrounds the tube near the insertion end just behind the drainage opening. After passing through the urethra, the balloon is inflated around the tube and rests on the wall of the bladder about the urethral opening, so as to retain the end of the catheter and the drainage opening therein inside the bladder. The balloon is deflated before withdrawing the catheter from the bladder.
One problem with such known catheters is that the drainage opening of the catheter is forward of the balloon. Therefore, the drainage openings do not drain urine which collects below the openings. This residual urine increases the chance of infection by providing a pool in which bacteria introduced into the bladder may grow.
Another problem with known catheters is the need to stock a large supply of different sizes. Currently, a catheter must be chosen for each patient having a diameter sufficiently large to seal the urethra to prevent urine leakage, but sufficiently small enough in diameter to pass through the urethra. As a result, most hospitals now carry approximately ten sizes of bladder catheters.
Another problem with commonly-used catheters is discomfort suffered by the patient during insertion of the catheter. The larger the diameter of the catheter, the more discomfort will be suffered by the patient incident to insertion through the urethra. The source of discomfort is that a large diameter catheter is required to seal against urine leakage. As previously discussed, in order to prevent urine leakage, a catheter with a diameter large enough to seal the urethra must be chosen. Any increase in the diameter of the catheter to effect sealing increases the discomfort suffered by the patient during insertion of the catheter through the urethra, as well as increased damage to the urethral lining.
Yet another problem exhibited by commonly-used catheters alluded to above, is discomfort suffered by the patient while the catheter is in place. The catheters are relatively stiff in order to facilitate insertion, and they do not conform to the individual patient's anatomy. The size and stiffness of the catheter inserted into the urethra, which is not perfectly tubular, forces the patient's urethra to conform to the catheter and causes discomfort to the patient while the catheter is in place.